Electrical meter



April 21. 1936. E.'W. GENT 2,038,277

ELECTRICAL METER Filed Jan. 10, 1955 lNl ENTOR By E. M. GENT A TTORNEV I P A... 21, 1930' g 2,038,277.

UNITED STATES PATENT OFFICE Edgar W. Gent, Morristown, N. 1., aasignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application January 10, 1935, Serial No. 1,118

3 Claims. (01. 171-95) This invention relates to electrical meters for the lamp 8 is focussed on the sensitive surface high voltage circuits, particularly current meters. of the photoelectric cell [2 thereby producing a An object of the invention is to simplify the current whichlis' in turn proportional to the light construction of electrical meters for high voltage intensity and 'which is read by the indicating 5 circuits. meter l5. By calibrating the meter I'd in terms 5 In a specific preferred embodiment of this inof the current in the bus-bar 8 a direct indicavention in a high voltage current meter, the contion of that current may be obtained. ductor which carries the current to.be measured y this n m n he 0111? Physical e is surrounded by a toroidal winding and the cur-. t n b tween the high voltage bus-bar 5 and the 10 rent induced in the winding is supplied toan in i a ing meter II is through the medium of 10 electrical lamp, the light from which is focussed t li ht b am so t at the indicatin m t r IS on a photoelectric cell which has its output 0011- is entirely electrically insu ated from he hi h nected to a meter calibrated to give an indication -8e blis- Obviously the light P maybe 0 of the current in the high voltage condu tor, any desired length to obtain the insulation neces- This invention can be more readily understood sary to meet the requir m y Voltage at 15 by reference to the following detailed description which the bus-bar 8 may be Operatedin connection with the drawing in which What is claimed is: l 1 shows aperspectlve view, and 1. A meter for use in high voltage circuits Flg, 2 ho a h ti diagram of n comprising a winding inductively coupled to the bodiment of the invention, similar reference (M61115, electrical 111? c nn ted to Said go numerals being used in connection with both w i s, a light sensitive cell, means for recting the light from said lamp on said cell, and Mounted on the high voltage bus-bar 5 h h a meter for measuring the electrical output of carries an alternating current which it is desired said cellto measure is a cylinder 6 of insulating material A current meter use w th h V l at mu is opaque t light A to m winding 1 buses, comprising a toroidal coil around said bus, isalso mounted on the bus-bar 5. Near the lower connections from said 0 t0 p. a light end of the cylinder 6 there is mounted an electric Sensitive 0811, means conwntratln! and directlight bulb 8 which is connected to the toroidal ing the light from said lamp on said cell,'and 0 winding 1 by means of wires 9. Mounted below means for measuring the output of said cellon a so, the bulb 8 is a reflecting mirror l0. At the upper device calibrated in terms of the current flowing end of the cylinder 8 there is provided a. mountin the bus. ing ll containing a photoelectric cell II. A con- 3'. A current meter for use with high voltage f densing lens l8 above the light bulb 8 focusses conductors, comprising a toroidal coil located 5 the light therefrom on the photoelectric cell l2 around and directly upon said conductor,- an as through the aperture ll. The photoelectric cell electric lamp energized by the current induced is connectedto an indicating meter l5. 8 in said coil, means comprising an opaque insu- The operation of the unit is as follows: Whe lator tube for eillciently directing the light from alternating current flows through the bus-bar said lamp on a light sensitive cell, and means for 40 5 it induces apropcrtional current in the toroidal measuring the output of said cell on a device 40 coil 1. This current is supplied to the lamp 8 calibrated in terms of the current flowing in the which is preferably a tungsten lamp and the bus, 1' light output of the lamp will be proportional to EDGAR W. GENT. the current in the coil I. The light radiated by v 

